Clutch control mechanism for motor vehicles



Dec. 26, 1939.

E. G. HILL 2,184,616

CLUTCH CONTROL MECHANISM FOR MOTOR VEHICLES Original Filed March 22,1935 2 Sheets-Sheet l CLUTCH CONTROL MECHANISM FOR MOTOR VEHICLESOriginal Filed March 22, 1935 2 Sheets-Sheet 2 mm. J9 5 64 liimfl 6? iQ- I a 5 54 55 w, 65 5 a g u k Patented Dec. 26, 1939 Ul'lEl) suresCLUTCH CONTROL MECHANISM FOR MO- TOR VEHICLES Edward G. Hill, Richmond,Va., assignor to Hill Engineering Corporation, Richmond, Va., acorporation of Virginia Application March 22,

1935, Serial No. 12,501

Renewed May 15, 1939 18 Claims.

This invention relates to clutch control mechanism for motor vehicles,and is an improvement over the structures shown in my prior Patent No.1,964,693, granted-June 26, 1934, and copending application Serial No.709,650, filed February 3, 1934.

In each of the prior constructions referred to I have proposed to employa vacuum operated power device for disengaging the clutch of a motorvehicle and controlled by a novel type of valve mechanism which wasoperative to provide extremely rapid clutch disengagement and to providesmooth clutch reengagement without any jerking or lunging of thevehicle. Such novel valve mechanism is described and claimed in my priorpatent referred to, and the operation of such valve mechanism accuratelysimulates conventional clutch operation under numerous conditions. Forexample, such valve mechanism accurately checks the movement oftheclutch elements as they approach operative position, depending uponthe mode of operation of the accelerator pedal, For example, if theaccelerator pedal is depressed relatively slowly, the clutch elementswill be checked substantially at the point of initial engagement, butwill be checked slightly later if the accelerator pedal is depressedmore rapidly, and such operation exactly follows the conventionaloperation of a vehicle clutch pedal. the necessity for adjusting thepoint at which the clutch elements will be checked, since the checkingaction is dependent upon actual contact of the clutch plates.

The functioning of the valve mechanism re ferred to further contemplatesthe progressive releasing of the clutch plate pressure'upon theprogressive releasing of the accelerator pedal toward idling position inorder to prepare the power mechanism for instantaneously disengaging theclutch when the accelerator pedal reaches idling position, thuspreventing any drag from being transmitted from the motor to the vehicledriving wheels. This progressive releasing of the clutch plate pressure,however, was dependent upon the torque reaction on the motor asreflected in the pressure in the intake manifold, and accordingly thereleasing of the clutch plate pressure would not take place to such. anextent as to cause any slippage of the clutch and undue wearing thereof.

The main valve mechanism described and claimed in my prior patent,therefore, is highly advantageous over prior constructions, but does nottake care of every desirable condition, For

Moreover, such construction eliminates example, While suoh valvemechanism operates to check the movement of the clutch elements atprogressively later points in accordance with the progressively morerapid opening movement of the engine throttle, such progressive actioncan check only up to a certain point beyond which grabbing of the clutchelements takes place. This is prevented in the prior constructionreferred to by providing what is termed a second check valve whichoperates independently of the main valve mechanism to check the movementof the clutch elements if the accelerator pedal is depressed toorapidly,

Moreover, while the valve mechanism disclosed in my prior patentreferred to was highly advantageous for use in shifting gears, it wasfound that when the device was used as a free wheeling device atsubstantial vehicle speeds, the depression of the accelerator pedal,when returning to normal operation, would result in full engagement ofthe clutch plates very slightly prior to the time at which the motorwould accelerate to a speed corresponding to vehicle speed, This slightlack of synchronism between clutch engagement and the acceleration ofthe motor speed took place only in a certain range of speeds, and thisfault was corrected by the mechanism disclosed in my copendingapplication referred to, Serial No. 709,650. In such mechanism, a.freewheeling valve was controlled by the degree of vacuum in the intakemanifold to act as a check on the second check valve in the range ofvehicle speeds referred to in which the slight jerking action tookplace, thereby retarding clutch engagement in such range of speed topermit the vehicle engine to accelerate to the proper speed before fullclutch engagement takes place.

An important object of the present invention is to provide a novel typeof control valve mechanism for clutch operating devices wherein all ofthe functions of the several devices previously referred to are carriedout in a single mechanism.

A further object is to provide a main control valve mechanism which isoperative for controlling the rate of clutch engagement upon thedepression of the accelerator pedal provided the rate of clutchengagement does not exceed a predetermined relationship with respect tothe torque load on the engine, and to provide an automatic valveoperative if such predetermined relationship is exceeded for taking thecontrolling of the rate of clutch engagement away from the main valvemechanism to prevent the too rap-id engagement of the clutch elements.

A further object is to provide an auxiliary valve 55 of the characterreferred to which is responsive to variations in the torque load bybeing made operative in accordance with variations in the degree ofvacuum in the intake manifold.

A further object is to provide a valve mechanism of the characterindicated which functions automatically in the several gear shiftingoperations for preventing the too rapid engagement of the clutchelements, and which functions automatically to provide smooth clutchengagement when returning to normal operation after free wheeling.

A further object is to provide a valve mechanism which includes a singlevalve automatically operative for performing the functions of the secondcheck valve and free wheeling valve referred to.

A further object is to provide such an automatic valve which functionsupon the relatively rapid operation of the accelerator pedal to graduatethe rate of clutch engagement in accordance with torque loads instead ofproviding a fixed rate of clutch engagement as is true in the case ofthe second check valve referred to.

In the drawings I have shown one embodiment of the invention. In thisshowing- Figure 1 is a side elevation of a motor vehicle engine andassociated parts showing the invention applied, part being broken away,

Figure 2 is a central vertical sectional view through the valvemechanism and associated elements, parts being shown in elevation,

Figure 3 is a detail sectional view on line 33 of Figure 2, and,

Figure 4 is a wiring circuit adapted for use in connection with theapparatus.

Referring to Figure 1, the numeral 9 designates the engine of a motorvehicle having the usual clutch in operated through the medium of a rockshaft ll. This shaft is conventionally operated by means of a clutchpedal i2. In the present instance, this pedal is loosely mounted on theshaft H and is provided with a lug I3 engageable against an arm M,secured to the shaft H, whereby it will be apparent that depression ofthe pedal I2 by the foot will effect clutch disengagement.

The engine illustrated in Figure l is of the V- type and the u' ualmanifold I5 is arranged be tween the two lines of cylinders and providedwith an upwardly extending inlet conduit it to the upper end of which isconnected a carburetor H. The air inlet of the carburetor is indicatedas being provided with an air cleaner !8.

The carburetor includes the usual butterfly throttle valve l9 carried bya shaft 20 projecting outwardly from the carburetor. An operating arm 2iis connected to the shaft 26 and is pivotally connected at its end toone end of a link 22. The other end of this link 22 is pivotallyconnected to an arm 23 forming one end of a lever, the other end 2 3 ofwhich constitutes the accelerator pedal. The pedal and arm 25? arepivotally supported as at 25 and a return spring 26 engages the arm 23to urge the throttle toward closed position.

The device forming the subject matter of the present invention comprisesa valve housing indicated as a whole by the numeral 27. This housingincludes a cylindrical main valve casing 2'8 in which a sleeve valve 29is vertically reciprocable. A stem 36 is connected to the upper end ofthe valve 29 and projects upwardly a substantial distance above thevalve casing, as clearly shown in Figure 2, A disk 3! surrounds the stem3i], and a compression spring 32 is arranged between this disk and thetop of the casing 28 to urge the valve 29 toward its uppermost position,as shown in Figure 2. The upper end of the stem, 30 is provided with ahead 33 operable by a cam indicated by the numeral 3 and secured to thevalve shaft 20. This cam includes high and low portions 35 and 36respectively, connected by a graduated intermediate portion El.

' The portion Eli of the cam is concentric with the axis of the shaftEli, and when such portion of the cam is in engagement with the head 33,the throttle is in its range of movement adjacent the fully openposition. When the throttle is closed, the high point 35 of the camengages the head 33 to maintain the valve 2E} in its lowermost position.

A second valve 33 is slidable within the valve 28. The valve 38 isprovided with upper and lower heads 39 and d9 spaced from. each otherand connected by a reduced shank 4 i. The valve 28 is provided withupper opposite arcuate ports 42 and a lower arcuate port 3, and theinner limits of the ports 52 and 63 are spaced apart a distancesubstantially equal to the distance between the valve heads 39 and ill,that is, a dis tance substantially equal to the length of the shank ii.Accordingly it will be apparent that the two valves 29 and 36 areadapted to assume positions with respect to each other in which theports 52 and 43 are disconnected from the port surrounding the shank MAt one side, the valve casing is provided with a radially extendingpassage M to the end of which a union 45 is connected. A pipe itconnects this union to the vertical intake pipe It. A valve M is movabledownwardly to close the passage M. This valve forms the armature of asolenoid 38 arranged in the casing 555 preferably formed integral withthe valve housing 2']. A light spring 59 urges the valve 'l'i downwardlyand the valve is movable to open position upon the energization of thesolenoid 58. Wires leading to this solenoid may be contained within acable 5!.

When the valve 29 is moved downwardly to bring the ports 42 intoregistration with the space around the shank M, communication will beafforded between the passage 44 and an opposite port 52 elongatedlongitudinally with respect to the valve 28 to bridge across both portsl2 and when the device is in operation, The port 52 communicates with apassage 53 in the outer end of which is threaded a union 5 5. One end ofa conduit 55 is connected to the union 5%. The other end of this conduitleads to a power device indicated as a whole by the numeral 55. Thispower device is operative for disengaging the clutch and may be of anydesired type, preferably of the vacuum operated type disclosed in myprior patent and copending application referred to. Such power deviceincludes a pair of casing sections 51 and 58, to the latter of which theconduit 55 is connected by a union 59. A dia phragm B8 is clampedbetween the casing Fections and is connected to a shaft 65! extendingfrom the casing section 51. The latter casing section is vented to theatmosphere as at 32, when the device is suction operated. The free endof the shaft El is connected to one end of a cable or othercorresponding element 63, and the other end of this element is connectedto the upper end of the arm It.

A pair of annular casing sections 64 and 65 is arranged at the lower endof the valve casing 21,

the casing section 64 preferably being formed integral therewith. Adiaphragm 66 is clamped between the casing sections 84 and 65 by meansof screws 67 passing through the edge portions of the casing sections.The lower end of the valve 49 is secured to the diaphragm 6G centrallythereof by means of a nut 58. The lower casing section 65 is providedwith an axial extension 69 in the end of which is threaded an adjustingscrew 19 secured in adjusted position by a lock nut H. Within theextension 59, a spring seat ?2 is mounted on the screw 19, and acompression spring i3 is arranged between the spring seat and thediaphragm 66 t urge the latter upwardly.

The casing section 64 is vented to the atmosphere as at 19, and means isprovided for establishing pressure difierential on opposite sides of thediaphragm 66 to operate the valve 38. The casing section '65 is providedadjacent its edge portion with a small port '15 communicating with aport 'E'G extending through the diaphragm 56. The housing 21 is providedwith a preferably integral member T! in which is formed a passage 18communicating at one end with the passage 53 and at the opposite endwith the passage 16. Thus it will be apparent that the chamber formedbetween the diaphragm 56 and the casing section 65 will be subject atall times to the pressure present in'the passage 53.

The casing 28 is provided with a lateral extension '59 having a passage85 extending therethrough, and the passages 53 and 89 preferably lie ina common plane transversely of the valve casing 28. The passages 53 andB9 communicate with the valve port 43, as clearly shown in Figure 3. Anauxiliary valve casing Si is preferably formed integral with theextension 19 and extends transversely thereof at its outer end, as shownin Figure 3. lhe valve casing 8! is provided with an atmospheric port 82arranged in alinement with the passage 89 and preferably provided with adust cap 83.

Means are provided for governing the degree of communication between thepassage and the atmosphere through the port 82. An auxiliary valve 84 isarranged within the casing 8!. The valve 8@ includes a cylindricalportion 85 at one end fitting and sliding within the casing 81. Fromsuch cylindrical portion the valve tapers toward its other end as at 85.The end of the casing 8! adjacent the tapered end of the valve 89 isprovided with a plug 8'! to limit the movement of the valve 84. .A union88 is threaded in the other end of the casing 8!, and a compressionspring 89 is arranged between this union and the cylindrical end 85 ofthe auxiliary valve to urge the latter toward the left as viewed inFigure 3. A conduit 89 has one end connected to the valve 35 and itsother end tapped into the main portion of the manifold i 5, as indicatedin Figure 1.

- A simple form of wiring diagram for the device is illustrated inFigure 4. The vehicle is provided with the usual battery 9!! grounded atone side as at 9i and having its other side connected as at 92 to theignition switch 93. This switch is engageable with the usual contact 94leading to the ignition system (not shown) of the vehicle. The contactEd is also connected by a wire 95 to a control switch S6 engageable witha contact 9?, and this contact is connected by a wire 98 to one terminalof the solenoid 48. The other terminal of this solenoid is connected bya wire 99 to a switch element ltd normally urged toward engagement witha contact 19 I, grounded as at 592. The vehicle is provided with theusual gear shifting mechanism (not shown) controlled by a gear shiftlever H03 and including a high gear shift rod 104. The switch elementI09 is supported with respect to the transmission by an insulating blockI05, and a similar block W6 is engageable by the shift rod I94 when thevehicle is in high gear to move the switch element I99 out of engagementwith the contact Hll.

One end of a Wire 101 is tapped into the wire 99 and has its other endconnected to an arcuate contact W8, preferably forming a part of thevehicle speedometer I09. The speedometer includes a brush H0, movable inaccordance with vehicle speed, and engageable with the contact 598 whenthe vehicle is traveling below a predetermined speed, such for example,as 10 miles per hour. A wire Hi connects the brush M9 to the ground asat H2.

A wire H3 leads from the wire it! to a push button l M arranged on theupper end of the gear shift lever and normally arranged in openposition. The gear shift lever is grounded as at H5, whereby it will beapparent that the wire H3 is grounded when the push button H4 isoperated. A manually operable switch H6 is connected to the wire i 91 asat I ii, and is movable into engagement with a contact i It, grounded asat I Hi.

The operation of the apparatus is as follows:

Assuming that the vehicle is at a standstill, the parts of the apparatuswill be in the positions indicated in Figure 1. The accelerator pedal isreleased and the parts wil be in idling position and the high point 35of the cam will be holding the stem 39 and valve 29 downwardly at theirlower limits of movement. Under such conditions, the ports 42 willafford communication between the passage 44 and port 52 around the steml l. At the same time, the port 63 will be arranged below the top of thevalve head 49. Under such conditions it will be apparent that thepassage 53, and hence the chamber within the casing section 58 of thepower device, will be connected to the intake manifold i5, assuming thatthe valve 4'! is open, while the power device will be disconnected fromthe passage 89, and hence will be disconnected from the atmosphere. Thevalve 38 will also be in its lower position,-since the vacuum present inthe passage 53 will be communicated through passages 15, 16 and 78 tothe chamber within the lower casing section 65. Thus the clutch will bedisengaged, and the operator is ready to start the vehicle.

The gear shift lever then may be placed in low gear position, whereuponthe operator may depress the accelerator pedal 24 in accordance with theusual practice. This operation rotates the cam 34 as the throttle opens,and the high point 35 of the cam will pass out of contact with the head33, whereupon the latter will start to move upwardly by engaging theintermediate cam portion 3?. The stem 39 and valve 29 accordingly willstart to move upwardly, whereupon the ports 62 will pass slightly abovethe-lower limit of the valve head 39, While the port 43 will moveslightly above the upper limit of the valve head 40. Under suchconditions, assuming that the accelerator is operated in accordance withthe normal practice, a substantial degree of vacuum will be present inthe manifold l5, and such vacuum will be communicated to the interior ofthe Valve casing 8! through pipe89 to hold the valve 84 toward the rightof its position shown in Figure 3. Thus air will be admitted intothepower device through ports 82, 80, 43, 52 and 53 and conduit 55. I

' celerator pedal is initially depressed and then.

In accordance with the usual practice, the clutch is biased towardengaged position, and as air is permitted to flow into the power device,the clutch elements will move toward engaged position under theinfluence of the clutch spring. The movement of the clutch elementsreferred to exerts a substantial pull on the diaphragm 60 of the powerdevice, causing such element to act somewhat in the nature of a vacuumpump to prevent the admission of air into the system from raising thepressure therein to any great extent. The partial vacuum still retainedin the system will depend upon three elements, as described in detail inmy copending application referred to. These three elements are thedegree of communication with the atmosphere as controlled by the port43, the area of the diaphragm and the rate of movement of such diaphragmunder the influence of the clutch spring. The partial vacuum thusmaintained in the system operates to maintain a sufficient pressuredifferential on opposite sides of the diaphragm 6G to prevent upwardmovement of the valve M, and

this valve will be momentarily retained in its lowermost position.

The relationship between the three elements r ferred to which determinethe degree of vacuum in the system when the accelerator is initiallydepressed will be altered upon the initial light contact of the clutchelements, since the movement of the diaphragm 69 will be retarded. Theresult of this action is to cause a slight increase in pressure in thesystem, and this increase in pressure is communicated to the atmospherewithin the lower diaphragm casing 65, thus sufficiently reducing thepressure differential on opposite sides of the diaphragm 66 to permitthe spring l3 to move the valve upwardly to cause the upper end of thevalve head 40 to close the port 43. At this time, assuming that theacstopped, no further air will be admitted into the system, and themovement of the clutch elements will be arrested substantially at thepoint of initial engagement.

If the accelerator pedal is then further depressed relatively slowly,the valve 29 will move slowly upwardly, thus again slightly opening theport 33 to admit additional air into the power device at a relativelyslow rate, thus moving the clutch elements to a position beyond initiallight contact toward a position of complete operative en agement. As thepressure increases in the system the pressure differential on oppositesides of the diaphragm 66 will be progressively reduced, thus permittingthe valve 38 to move progressively upwardly, whereby the upper end ofthe valve head tends to follow the upper limit of the port E3 todisconnect the system from the atmosphere. If the operator continues toslowly depress the accelerator pedal, the valve 29 will continue to moveprogressively upwardly, while the same action takes place with respectto the valve 38, but the upper end of the head 40 will lag behind theupper limit of the port 43, thus permitting the continued introductionof air into the power device until pressure equalization on oppositesides of the diaphragm 60 is reached, at which time the clutch elementsare in complete operative engagement.

The rate at which air is admitted into the power device obviously willbe determined by the rate of openingmovement of the throttle. As thethrottle opens more rapidly, the valve 29 moves upwardly at the samerate, thus maintaining a larger efiective opening of the port 43 thanwhen the accelerator is depressed more slowly. Accordingly it will beapparent that the rate at which the clutch elements are brought intooperative engagement will be dependent upon the rate of throttleoperation. It likewise will be apparent that the point at which themovement of the clutch elements will be initially checked is dependentupon the mode of operation of the accelerator. If the accelerator isinitially depressed relatively slowly, the movement of the clutchelements will be checked approximately at the point of initialengagement. If the operator desires to get under way more rapidly, hemay depress the accelerator pedal more rapidly, in which case the morerapid upward movement of the port 63 with respect to the valve head 40will cause the latter to travel somewhat further before closing the port43 and disconnecting the power device from the atmosphere, andaccordingly the checking of the clutch elements will occur later.

As fully disclosed in my prior patent referred to, the main valvemechanism also functions to release the clutch plate pressure as thethrottle approaches closed position, under normal conditions, thusrendering complete clutch disengagement much more rapid when theaccelerator is fully released. As the accelerator is progressivelyreleased in the range of movement adjacent the idling position, the camportion 3? will travel over the head 33, thus gradually moving the valve29 downwardly. This operation affords progressive slight communictionbetween the passage 44 and port 52, while the port 43 will be arrangedbelow the upper limit of the valve head 40. Thus the vacuum in theintake manifold acts slowly before the idling position is reached tobuild up a pressure difierential on opposite sides of the diaphragmwill, tending to disconnect the clutch. The pressure differential willbe insufllcient to completely disengage the clutch, however, until thethrottle reaches idling position. If, during movement of the throttletoward idling position its movement should be stopped before the idlingposition is reached, there will be no further downward movement of thevalve 29, and the continued gradual reduction in pressure in the passage53 will be communicated to the lower diaphragm chamber 65 to move thevalve 38 downwardly and thus disconnect the power device from thevacuum.

Thus it will be apparent that the clutch plates will not be released toa greater extent than. the accelerator pedal is moved toward idlingposition, and since engine speed and torque are reduced as clutch platepressure is reduced there will be no tendency for the clutch to slip.The resulting action is comparable to the riding of the c-..tch but thisis of no consequence since the throw out bearings of present dayclutches are adapted to withstand such action. If, given e1. speed, thetorque load should increase, the o, tor will compensate for this byfurther -c ing the accelerater pedal to hold the same speed, and thefurther opening movement of the throttle thus moves the vaive upwardlyand admits air into the power device through port 43 whileclisccnnecting the power device from the intake manifold- The clutchplate pressure thus will increase in proportion to the engine torque,and slippage of the clutch will be prevented.

While the previously described operation of shifting gears and thendepressing the accelerator pedal has been described with relation to lowgear, it will be apparent that all of the various operations take placeregardless of the position of the gear shift lever. For example, if thegear shift lever is in low gear and the accelerator pedal is depressedto accelerate the engine and to secure partial or complete clutchengagement and thus cause the vehicle to travel forwardly, trafficconditions may require that the operator partially release theaccelerator before continuing through the gear shifting operations, andthe partial releasing of the accelerator pedal will release the clutchplate pressure in the manner previously described. If the accelerator isreleased toa sufficient extent, clutch engagement will be present onlyto a slight extent, thus tending only slightly to move the vehicleforwardly. If the accelerator is completely released, the clutch will besimilarly released to completely disconnect the engine from the drivingwheels.

Moreover, it will be apparent that the rate of clutch engagement dependsupon the rate of accelerator operation regardless of the position of thegear shift lever, and accordingly the previously described operation ofthe clutch takes place in every gear. Thus it will be apparent thatafter complete clutch engagement has taken place in low gear, theaccelerator may be released to effect clutch disengagement, whereuponthe gear shift lever may be moved into second gear position. The factthat the clutch plate pressure is progressively released as theaccelerator is released causes complete clutch disengagement to takeplace as soon as the accelerator returns to idling position, thuspreventing any drag from being transmitted frcm the motor to the drivingwheels. The operation is repeated for the several gears, and at eachshifting of the gears, the previously described disengagement of theclutch takes place. In accordance with conventional operation, theaccelerator pedal is preferably depressed relatively slowly when thevehicle is in low gear, while somewhat more rapid depression of theaccelerator and engagement of the clutch may take place in second gearsince the vehicle will have gained substantial momentum. It further willbe apparent that even faster accelerator operation and clutch engagementmay take place in high gear due to the even greater momentum of thevehicle. These several results are readily accomplished by the operationof the valve mechanism described.

As stated above, relatively slow or relatively rapid acceleratoroperation and clutch engagement is under the control of the operator,but this is true only within'reasonable limits. It will be apparent thatwhen the vehicle is in low gear, for example, the relatively rapidoperation of the accelerator readily may cause clutch engagement to takeplace too rapidly, considering that the vehicle is at a standstill, andin my prior patent referred to, I have provided a second check valvewhich is operative upona substantial increase in pressure in the powerdevice to act as a check on the main valve mechanism to prevent the toorapid increase in pressure in the power device. Such valve permits theoperator to control the operation of the main valve mechanism withinreasonable limits in accordance with the operation of the accelerator,and beyond such limits, the second check Valve takes the controlling ofthe clutch engagement away from the main valve mechanism and limitsto afixed extent the supply of air to the power device.

The valve 8 3, among other functions, performs the function of thesecond check valve referred to in a highly improved manner. Whereas thepreviously developed second check valve is con.- trolled by theincreases in pressure in the power device, the valve 84 is controlled bythe partial vacuum in the intake manifold, which in turn, is dependentupon the torqueload on the engine.

Moreover, whereas the second check valve referred to when operating,limits to a constant rate the admission of air. into the power device,the valve 8 3 graduates the admission of, air in accordance with torqueconditions.

The pipe 29 is preferably tapped into the main manifold l5, inasmuch asthe pressure in such manifold portion fluctuates less than is true ofthe vertical pipe It, being more closely related to variations in torqueloads. These pressure variations are comimmicated to the chamber 81,through the pipe 89, while the reduced end portion of the valve 84 isinfluenced by atmospheric pressure. During the clutch engaging functionsof the main valves 29, and 38 the valve 84 does not function if theaccelerator is not pressed too rapidly, since under such conditions, thepartial vacuum in the manifold 15 and in the right hand end of thechamber 8!, as viewed in Figure 3, is sufficient to retract the valve 84to such an extent that the tapered end 86 thereof permits the flow ofair between the opening 82 and the passage Bil at least as rapidly asair will be admitted into the power device through the port 43. Undersuch conditions, therefore, the Valve 84 will vary its position inaccordance with fluctuations of the pressure in the manifold I5, butdoes not affect the operation of the power device.

Assuming that the operator depresses the accelerator pedal relativelyrapidly whereby the normal operation of the main valve mechanism wouldrelease the clutch elements for operative engagement suflicientlyrapidly to cause the vehicleto jerk or lunge, as, for example, in firstor second gears, the valve 84 will come into operation to take over thecontrolling of the power device and render the main valve mechanisminoperative .for this purpose. Under such conditions, the relativelyrapid operation of the accelerator will cause a sudden and substantial.

increase in pressure in the intake manifold and this pressure will becommunicated to the casing 31 to reducethe differential pressure onopposite sides of the valve 84. The spring 89' will thereuponmove thevalve 84 toward the left as viewed in Figure 3, to reduce communicationbetween the opening 82 and passage 80. Since the portion of the valve 84which will thus move past the opening 82 and passage 89 is tapered, thedegree to which communication therebetween will be reduced will dependupon the degree of movement paratus provides two control valvemechanisms,

one of which operates to provide clutch engagement in accordance withthe rate of operation of the throttle, and the other of which operatesabove a given rate of throttle operation to control clutch engagement inaccordance with engine torque. The function of the valve 84 accordinglyprovides the function of the second check valve referred to in that itprevents too sudden clutch engagement, but this operation goessubstantially further in that it provides a graduated rate of clutchengagement in accordance with the conditions present.

In my copending application Serial No. 709,650, I have disclosed a mainvalve mechanism similar to the corresponding mechanism of the presentapplication and supplemented by an auxiliary valve for smoothing out theoperation of the main valve mechanism when the device is used for freewheeling, in a manner to be described. Such auxiliary valve was operablein the chamber similar to the chamber 8| and was responsive to pressuresin the manifold 5 to the extent that during the presence of certainpressures within the manifold, the auxiliary valve would operate torestrict the flow of air into the power device. Such valve, however, didnot contemplate the uses of the present valve inasmuch as it did notprovide for the admission of air at graduated rates in accordance withtorque loads. The present valve however, functions tosmooth out theoperation of the valve mechanism when the device is used for freewheeling.

The device is preferably provided with the electrical circuits shown inFigure 4 to provide selective operations, and when one of these circuitsis employed in a manner to be described, the clutch will be released ateach releasing of the accelerator pedal 24 regardless of any otherconditions. Thus it will be apparent that when the vehicle is travelingin high gear and the accelerator is released, the clutch will bereleased, thus providing free wheeling or coasting in high gear. In theabsence of an auxiliary valve of the type of the valve 84 or the freewheeling valve disclosed in my copending application referred to, themain valve mechanism does not function smoothly under all conditions toprovide clutch reengagement. If the vehicle is traveling at asubstantial speed, it is necessary when returning to normal operation toaccelerate the engine speed rapidly to a point corresponding to vehiclespeed, and this point in engine speed should be reached beforesubstantial clutch engagement takes place, otherwise the engine will actas a partial brake to slow down the speed of the vehicle, the operationreferred to causing a very perceptible dragging in vehicle speed.

If the present device is employed as a free wheeling unit and thevehicle speed is below a predetermined point, the engine speed may bepromptly brought up to a corresponding point by depressing theaccelerator pedal to the proper extent without causing a sufficientincrease in the manifold pressure to render the valve 84 operative.Under such conditions, clutch reengagement will be controlled wholly bythe main valve mechanism. Assuming that the vehicle speed is relativelyhigh, for example, above fortymiles perhour,and the operator desires toresume normal driving conditions after having been free wheeling, therapid depression of the accelerator pedal to a sufficient extent toaccelerate the engine speed to a point corresponding to vehicle speedwould cause the main valve mechanism to operate to permit air to flow sorapidly into the power device as to permit clutch engagement to takeplace to a substantial extent before the proper engine speed has beenreached. With the present device, however, such operation of theaccelerator will result in a sudden and substantial increase in pressurein the manifold, in which case the valve 84 will move to the positionshown in Figure 3 and will substantially limit the flow of air into thepower device. Thus the main valve becomes ineffective for controllingclutch reengagement, this function being taken over by the valve 8%, andthe restriction in the flow of air into the power device delays clutchengagement until the, engine has had time to accelerate to the desiredpoint. Thus it will be apparent that the valve 84 provides the functionof the free wheeling valve of my copending application referred to; thatit provides the function of the second check valve of my prior patentreferred to, and that it constitutes a substantial improvement over thelatter valve in that it provides a graduated clutch engagement inaccordance with torque loads when the accelerator is operated relativelyrapidly in gear shiftmg.

The wiring system in Figure 4 is relatively simple and providesselective systems of operation. Assuming that the switch H5 is open andthe ignition switch is closed, a circuit will be completed through thesolenoid 48 to maintain the valve 41 open at all times except when thevehicle is in high gear and traveling above a predetermined speed. Suchcircuit includes the battery 90, wire 92, switch 93, wires 95 and 98,solenoid 88, wire 99, switch Hi0, and grounds I02 and 9!. Under suchconditions each releasing of the accelerator pedal will effect clutchdisengagement, since the inner end of the passage 44 will be in fixedcommunication with the intake manifold whereby the operation of thepower device is dependent wholly upon the operation of the valves 29 and38. Whenever the valve 29 is moved downwardly for releasing theaccelerator, therefore, the clutch will be disengaged.

Assuming that it is desired to use the engine as a brake in high gear,the switch H6 may be left open at all times, and the previouslydescribed circuit will remain closed at all times except when thevehicle is in high gear. When the gear shift lever is moved to high gearposition, the shift rod I04 opens the switch I00, and the circuitreferred tocan be completed beyond the wire 99 only through the buttonH4, or through the switch including the contact I08 and brush H0. Whenthe vehicle is traveling above a predetermined speed in high gear, forexample, above 10 miles per hour, the brush III] will be arranged beyondthe contact me and the circuit through the solenoid 48 will be broken.The valve 47 thus will be projected to closed position and the releasingof the accelerator pedal cannot afiect the power device since theoperation of the valves 29 and 38 cannot connect the power device to theintake manifold.

Under the conditions described, the accelerator may be released at anytime and the engine will act as a brake in accordance with conventionalpractice. Assuming that a driver releases the accelerator pedal with theintention of bringing the vehicle to a stop, the vehicle speed willprogressively decelerate until the predetermined speed referred to isreached, whereupon the circuit through the solenoid will be completedfrom wire 99 through wire I01, contact I08, brush Ill] and ground H2.The valve 41 will be promptly opened, and since the valve 29 under suchconditions will be arranged in its lower position, the clutch will bedisengaged, whereupon the vehicle may be brought to a standstill.

If it is desired to employ the device as a free wheeling unit withclutch disengagement occurring at each releasing of the acceleratorpedal, it is merely necessary to close the switch H6,

in which case the circuit from the wire 99 will remain closed at alltimes through wire lD'l, switch H6 and ground H9. The operation of theshift rod IE4 or the brush H cannot affect this circuit, and the valve41 will remain open at all times, thus affording constant communicationbetween the inner end of the passage 44 and the manifold so as toconnect the latter to the power device upon each releasing of theaccelerator pedal.

The button I M is provided merely for the purpose of allowing theoperator to effect declutching at any time when such action would nototherwise occur through the releasing of the accelerator pedal. Forexample, if the vehicle is traveling in high gear above thepredetermined speed of ten miles per hour with the switch H6 open, thebrush i it will be arranged beyond the contact H38 and if theaccelerator pedal is released, the clutch will not be disengaged sincethe valve 4*! will be in closed position. If, under such conditions, thevehicle starts to ascend a relatively steep hill, the operator maydesire to shift into second gear promptly without waiting for thevehicle speed to decelerate to the point at which the solenoid circuitwill be closed by engagement of the brush III! with the contact H18. Itmerely is necessary under such conditions for'the operator to releasethe accelerator pedal and depress the button H4 which closes a shuntcircuit around the switch I00 and brush H0 by connecting the wire 99 toground H5 through wires W5, and l 13, and through the button switch l94.

From thefor'egoing it will be apparent that the present device is highlyefiicient in operation as a clutch control mechanism for gear shiftingand for free wheeling. It also will be apparent that the valve 84,operating in conjunction with the main valve mechanism, takes care ofseveral operating conditions so as to provide smooth clutch engagementeither when shifting gears or when returning to conventional operationafter free wheeling, all jerking or lunging of the vehicle beingeliminated. 1

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as a preferred example of the same and thatvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

I claim:

1. Clutch control mechanism for a motor vehicle having a motor and aclutch, comprising a power device connected to the clutch, and controlmechanism for effecting actuation of the power device to disengage theclutch and for controlling the power device to effect clutch engagementat variable rates, including means for assuming control of the powerdevice to effect clutch engagement' substantially in accordance withtorque loads on the engine if said control mechanism tends to efiectclutch engagement at a rate exceeding a given relation to the torqueload on the engine.

2. Clutch control mechanism for a motor vehicle having a motor and aclutch, comprising a power device connected to the clutch, and controlmechanism for effecting actuation of the power device to disengage theclutch and for controlling the power device to successively release theclutch elements for movement toward operative engagement, check themovement of the clutch elements at a point prior to full operativeengagement, and then effect movement of the clutch elements into full.operative engagement at Variable rates, including means for assumingcontrol of the power device during the movement of the clutch elementsinto full operative engagement substantially in accordance with torqueloads on the engine if said control mechanism tends to effect clutchengagement at a rate exceeding a given relation to the torque load onthe engine.

3. Clutch control mechanism for a motor vehicle having a clutch and anengine provided with a throttle, comprising a power device connected tothe clutch, and control mechanism operative coincidentally with theengine throttle for effecting actuation of the power device to disengagethe clutch upon closing movement of the throttle and for controlling thepower device upon opening movement of the throttle to effect clutchengagement at variable rates, including means for assuming control ofthe power device to effect clutch engagement substantially in accordancewith torque loads'on the engine if said control mechanism tends toeffect clutch engagement at a rate exceeding a given relation to thetorque load on the engine.

4. Clutch control mechanism for a motor vehicle having a clutch and anengine provided with a throttle, comprising a power device connected tothe clutch, and control mechanism operative coincidentally with theengine throttle for effec ing actuation of the power device to disengagethe clutch upon closing movement of the throttle and for controlling thepower device upon opening movement of the throttle to successivelyrelease the clutch elements for movement toward operative engagement,check the movement of the clutch elements at a point prior to fulloperative engagement, and then effect movement of the clutch elementsinto full operative engagement at variable rates, including means forassuming control of the power-device during the movement of the clutchelements into full onerative engagement substantially in accordance withtorque loads on the engine if said control mechanism tends to efiectclutch engagement at a rate exceeding a given relation to the torqueload on the engine.

5. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold, comprising a differentialpressure power device connected to the clutch, and control valvemechanism for controllling communication between said power device andthe intake -manifold to effect actuation of the power device todisengage the clutch and for controlling the power device to eifectclutch engagement at variable rates, including auxiliary valve means forassuming control of the power device to effect clutch engagementsubstantially in accordance with torque loads on the engine if saidcontrol valve mechanism tends to efiect clutch engagement at a rateexceeding a given relation to the torque load on the engine.

6. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold, comprising a differentialpressure power device connected to the clutch, and control valvemechanism for controlling communication between said powerclevice andthe intake manifold to effect actuation of the power device to disengagethe clutch and for controlling the power device to successively releasethe clutch elements for movement toward operative engagement, check themovement of the clutch elements at a point prior to full operativeengagement, and effect movement of the clutch elements into fulloperative engagement at variable rates, including auxiliary valve meansfo control of the power device during a move..- ent of the clutchelements into full tpera-vc engagement substantially in accord withtorque loads on the engine if said control valve mechanism tends toeffect clutch engagement at a rate exceeding a given relation to thetorque load on the engine.

Clutch control mechanism for a motor vehicle having a clutch and a motorprovided with an intake manifold and a throttle therefor, a differentialpressure power device connected to the clutch, and control valvemechanism operative coincidentally with the throttle for efiectactuationor the power device to disengage the clutch upon closing movement of thethrottle and for controlling the power device upon opening movement ofthe throttle to effect clutch engagement at variable rates, includingauxiliary valve means for assuming control of the power device to effectclutch engagement substantially in accordance with torque loads on theengine if said control valve mechanism tends to effect clutch engagementat a rate exceeding a given relation to the torque load on the engine.

8. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold and a throttle therefor, adiiierential pressure power device connected to the clutch, and controlvalve mechanism operative coincidentally with the throttle for effectingactuation of the power device to disengage the clutch upon closingmovement of the throttle and for controlling the power device uponopening movement of the throttle to successively release the clutchelements for movement toward operative engagement, check the movement ofthe clutch elements at a point prior to full operative engagement, andthen effect movement of the clutch elements into full operativeengagement variable rates, including auxiliary valve means for assumingcontrol of the power device during the movement of the clutch elementsinto full operative engagement substantially in accordance with torqueloads on the engine if said control mechanism tends to effect clutchengagement at a rate exceeding a given relation to the torque load onthe engine.

9. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold, a differential pressure powerdevice connected to the clutch, and control valve mechanism forcontrolling communication between said power device and the intakemanifold and the atmosphere for effecting actuation of the power deviceto disengage the clutch and for controlling the power device to efiectclutch engagement at variable rates, including auxiliary valve iorcontrolling communication between said power device and the atmospherefor controlling the power device to effect clutch engagementsubstantially in accordance with torque loads on the engine if saidcontrol valve mechanism tends to effect clutch engagement at a rateexceeding a given relation to the torque load on the engine.

1' Clutch control mechamsm for. a motor ve hicle having a clutch and amotor provided with an intake manifold, a differential pressure powerdevice connected to the clutch, and control valve mechanism forcontrolling communication between said power device and the intakemanifold and the atmosphere for effecting actuation of the power deviceto disengage the clutch and for controlling the power device tosuccessively re lease the clutch elements for movement toward operativeengagement, check the movement of the clutch elements at a point priorto full operative engagement and then efiect movement of the clutchelements into full operative engagement at variable rates, includingauxiliary valve means for controlling the degree of communicationbetween said power device and the atmosphere for controlling the powerdevice during the movement of the clutch elements into full operativeengagement substantially in accordance with torque loads on the engineif said control valve mechanism tends to effect clutch engagement at arate exceeding a given relation to the torque load on the engine.

11. Clutch control mechanism for a motor vehicle having an engine and aclutch, comprising a differential pressure power device connected to theclutch, and control valve mechanism for disconnecting said power devicefrom the atmosphere and connecting it to a source of pressuredifi'erential to disengage the clutch and for disconnecting the powerdevice from the source of pressure differential and connecting it to theatmosphere to effect clutch engagement, an auxiliary control valve forsaid power device, said auxiliary valve being biased in one directionand being urged in the other direction to a variable extent dependingupon the torque load on the engine and being operative for limitingcommunication through said first named valve between said power deviceand the atmosphere substantially in accordance with the torque load onthe engine.

12. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold, comprising a diiierentialpressure power device connected to the clutch, and control valvemechanism. for disconnecting said power device from the atmosphere andconnecting it to a source of pressure differential to disengage theclutch and for disconnecting the power device from the source ofpressure differential and connecting it to the atmosphere to effectclutch engagement, said valve mechanism including a valve forcontrolling movement of the clutch elements into operative engagementand further including an auxiliary valve for providing graduatedcommunication through said first named valve between said power deviceand the atmosphere, and means for positioning said valve in accordancewith the degree of vacuum in the intake manifold to limit the rate ofclutch engagement in accordance with manifold vacuum.

13. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold, comprising a differentialpressure power device connected to the clutch, and control valvemechanism for disconnecting said power device from the atmosphere andconnecting it to a source of pressure differential to disengage theclutch and for disconnecting the power device from the source ofpressure differential and connecting it to the atmosphere to effectclutch engagement, said valve mechanism including a valve forcontrolling movement of the clutch elements into operative engagementand further including a tapered valve controlling communication throughsaid first named valve between said power device and the atmosphere,means biasing said valve in one direction, and a conduit connected atone end to the intake manifold and influencing said auxiliary valve totend to urge it in the other direction in accordance with decreasedpressures in the intake manifold.

14. Clutch control mechanism for a motor vehicle having a clutch and amotor provided with an intake manifold comprising a differentialpressure power device connected to the clutch, and control valvemechanism for disconnecting said power device from the atmosphere andconnecting it to a source of pressure differential to disengage theclutch and for disconnecting the power device from the source ofpressure differential and connecting it to the atmosphere to effectclutch engagement, including a valve casing, a tapered valve in saidcasing controlling communication between said power device and theatmosphere through said control valve mechanism, a spring tending tourge said tapered valve in one direction to limit communication with theatmosphere, and a conduit connecting said valve casing to the intakemanifold to urge said tapered valve progressively in the other directionin accordance with progressively decreasing pressures in the intakemanifold.

15. Clutch operating mechanism for a motor vehicle having a clutch andan intake manifold, comprising a power device connected to the clutch,and means for rendering said power device operative for disengaging theclutch and for releasing the clutch elements for controlled movementinto operative engagement, including means operative through said firstnamed means for assuming control of the rate of clutch engagement whensaid first named means tends to release the clutch elements for movementinto operative engagement at a rate faster than a predetermined rate inproportion to the degree of vacuum in the intake manifold.

16. Clutch operating mechanism for a motor vehicle having a clutch andan intake manifold, comprising a differential pressure power device, andvalve means for rendering said power device operative for disengagingthe clutch elements and for releasing the clutch elements for controlledmovement into operative engagement, including valve means controlled bythe degree of vacuum in the intake manifold for assuming control of saidpower device to determine the rate of clutch engagement when said firstnamed valve means tends to release the, clutch elements for movementinto operative engagement at a rate faster than a predetermined rate inproportion to the degree of vacuum in the intake manifold.

1'7. Clutch operating mechanism for a motor vehicle having a clutch andan intake manifold, comprising a differential pressure power device, andvalve means for controlling communication between said power device andthe intake manifold and atmosphere to render the power device operativefor disengaging the clutch and for releasing the clutch elements formovement into operative engagement, including a floating valve movablein accordance with the degree of vacuum in the intake manifold andoperative for controlling communication between said power device andthe atmosphere when said valve means tends to release the clutchelements for movement into operative engagement at a rate faster than apredetermined rate in proportion to the degree of vacuum inthe intakemanifold.

18. Clutch'operating mechanism for a motor vehicle having a clutch andan intake manifold, comprising a diiferential pressure power device, andvalve means for controlling communication between said power device andthe intake manifold and atmosphere to render the power device operativefor disengaging the clutch and for releasing the clutch elements formovement into operative engagement, an atmospheric conduit through whichsaid valve means controls communication between said power device andthe atmosphere, said valve means including a floating valve controllingcommunication through said conduit to control the rate of engagement ofthe clutch elements when said valve means. tends to release the clutchelements for movement into operative engagement at a rate faster than apredetermined rate in proportion to the degree of vacuum in the intakemanifold.

EDWARD G. HILL.

